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Re: What is Cygwin DLL & emulation Layer ?
Neeraj Sahu wrote:
Why you have designed cygwin as DLL ? What's the advantage ?
The advantage relative to what? Propose another way it could work, and
we can compare and contrast the alternatives.
What is Cygwin emulation layer ?
cygwin1.dll. It sits between POSIX type programs and the Windows API,
allowing these programs to believe they are running on a POSIX type
operating system, so they don't have to know how to use the Windows
equivalent APIs.
In addition to the Cygwin DLL, there is also a huge library of POSIX
software ported to use the DLL, to provide a complete POSIX operating
environment. These things are not Cygwin proper, but they are
considered part of a working Cygwin system, in the same way that the
Linux kernel is only part of a complete "Linux" operating system.
How Cygwin work internally. Please explain in brief ?
The Cygwin DLL translates POSIX system calls into Windows system calls.
Where there is no exact match between the behavior of Windows and the
expected behavior on a POSIX operating system, the Cygwin DLL provides
the functionality to make up the gap. In some places the "thickness" of
the DLL is very thin, while in other places it has to do a lot of work
to provide POSIX behavior in terms of the Windows API.
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